For simple concatenation file having one format, for example, documents, use a program like PDF Split-Merge. Download it by clicking the link http://www.pdfsam.org/?page_id=32 and select the file you want. Install the app, then run it. Follow the menu items, select menu of the program responsible for the process of joining files. Add the documents you need in the working field of the program and set priorities, and then determine the name and the location of the end of the file, and then start the process.
If you need to glue the individual pages from multiple pdf files, use Foxit PhantomPDF. Click on the link http://www.foxitsoftware.com/downloads/ and download the version that suits you. With this program you can not only cut and re-glue several different documents, but to edit the text, fonts, and create new documents. You can also optimize the pdf based on desired file size and quality.
Often, you may encounter files which are protected from printing and editing. In this case you need to convert them into images, and then organize the resulting images, respectively, of the desired order and create one pdf file. This is feasible by using two simple applications – Pdf to Jpg Converter, JPG To PDF Converter. Download them by clicking on the links http://www.pdf-to-jpg.com/ and http://www.jpgtopdfconverter.com/, respectively. Install the application.
With Pdf to Jpg Converter put the desired files in the image, and then number the images in accordance with the desired order of pages in the resulting document. Run JPG To PDF Converter and add them to the artboard, strictly observing the desired sequence. Then, specify the name and location of the destination file and start the conversion process.